As was discussed in my prior U.S. Pat. No. 4,063,833, there are a variety of prior art devices to adjust the length of a member. One such device is disclosed in U.S. Pat. No. 253,313, where an elongate coupling sleeve joins a rod with a right screw thread to a rod with a left screw thread, the rods being colinear. The rotation of the sleeve in one direction draws the rods together along their common axis and the rotation of the sleeve in the opposite direction pushes the rods apart. Thus, the overall length of the rods in this colinear arrangement can be adjusted. A disadvantage with the arrangement is the threads on the rods are not always covered by the sleeve, as, for example, when the rods are fully extended out of the sleeve. The threads so exposed, are susceptible to a corrosive environment. Additionally, any lubricating fluids placed on the exposed threads tend to become removed therefrom by, for example, the threads being rubbed against another object. Further, exposed threads create a safety hazard in that, for example, fingers can be caught between the threads and the sleeve as the rods are pulled into the sleeve.